An exhaust pipe flange gasket bears a clamping load from a bolted joint involving the connection of two pipe-like members having flanges and opposing planar faces. The gasket relies upon that load to prevent exhaust gases and other materials from escaping through the joint from one member to the other.
One known gasket comprises composite material which compresses under installation pressure, causing mating flanges to deform and bend. A non-uniform sealing stress distribution may be created, depending on the degree of flange deformation and the corresponding variable gasket compression. Further, the material is exposed to exhaust gases that can degrade the composite material. A shielding grommet may be added, but higher stresses resulting from the grommet may aggravate the flange deformation.
Another known ring-like gasket requires a machined groove or recess in the mating flange for the proper installation of the gasket. Gasket stress and compression are determined by the construction of the gasket and the depth of the recess. When the gasket is fully compressed in the recess, a positive metal to metal lock may be achieved at mating opposing planar faces of the flanges to minimize bending. However, the installation location of the gasket is dependent on the location of the recess and the ability to maintain gasket position during installation. One method of devising a positive lock location of the gasket is to create an interference fit between an inner diameter of the recess and the minor inner diameter of an elliptically shaped ring-like gasket. Close tolerances are required between the machined recess and the gasket.
A ring-like gasket may also be installed over an extended length pipe-like member having a planar face adapted to mate with a planar face of a corresponding member. For most applications, however, alignment of the respective opposing planar faces is extremely difficult because of the extended length of the pipe-like member. Further, interference fits are difficult because of outer diameter variability related to the pipe-like member.
Finally, a ring-like gasket may be installed in a recess of a flanged pipe-like member and held in place by gravity. However, the member is usually angled during assembly, allowing the gasket to fall out of the recess.